1. Technical Field
This invention relates to an image processing apparatus, an image processing method, a computer readable medium storing an image processing program and a data signal embedded with the program, particularly to an image processing apparatus, a computer readable medium storing an image processing program and a data signal embedded with the program for calculating a position shift amount between two pieces of image data and performing a correction process for position alignment.
2. Related Art
In the field of image processing, there are many cases where position alignment between images on two paper documents of identical type is demanded. For instance, in the case of extracting information filled in (added) by a user on a paper document, such as a legal sheet and a resume, output by a printer or a fax (facsimile apparatus) from the paper document or in the case of examining as to whether or not a security document has been falsified, a process of detecting the added information or the falsified part by comparing scan image data obtained by scanning the paper document with original image data of an electronic original is performed. In this detection process, it is necessary to perform position alignment between the scan image and the electronic original image with high accuracy before making comparison between the scan image data and the original image data.